1 /*******************************************************************************
3 Intel 10 Gigabit PCI Express Linux driver
4 Copyright(c) 1999 - 2010 Intel Corporation.
6 This program is free software; you can redistribute it and/or modify it
7 under the terms and conditions of the GNU General Public License,
8 version 2, as published by the Free Software Foundation.
10 This program is distributed in the hope it will be useful, but WITHOUT
11 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 You should have received a copy of the GNU General Public License along with
16 this program; if not, write to the Free Software Foundation, Inc.,
17 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
19 The full GNU General Public License is included in this distribution in
20 the file called "COPYING".
23 Linux NICS <linux.nics@intel.com>
24 e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
25 Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
27 *******************************************************************************/
31 #include "ixgbe_type.h"
32 #include "ixgbe_dcb.h"
33 #include "ixgbe_dcb_82598.h"
34 #include "ixgbe_dcb_82599.h"
37 * ixgbe_dcb_calculate_tc_credits - Calculates traffic class credits
38 * @ixgbe_dcb_config: Struct containing DCB settings.
39 * @direction: Configuring either Tx or Rx.
41 * This function calculates the credits allocated to each traffic class.
42 * It should be called only after the rules are checked by
43 * ixgbe_dcb_check_config().
45 s32 ixgbe_dcb_calculate_tc_credits(struct ixgbe_hw *hw,
46 struct ixgbe_dcb_config *dcb_config,
47 int max_frame, u8 direction)
49 struct tc_bw_alloc *p;
52 int min_percent = 100;
54 /* Initialization values default for Tx settings */
55 u32 credit_refill = 0;
57 u16 link_percentage = 0;
61 if (dcb_config == NULL) {
62 ret_val = DCB_ERR_CONFIG;
66 min_credit = ((max_frame / 2) + DCB_CREDIT_QUANTUM - 1) /
69 /* Find smallest link percentage */
70 for (i = 0; i < MAX_TRAFFIC_CLASS; i++) {
71 p = &dcb_config->tc_config[i].path[direction];
72 bw_percent = dcb_config->bw_percentage[direction][p->bwg_id];
73 link_percentage = p->bwg_percent;
75 link_percentage = (link_percentage * bw_percent) / 100;
77 if (link_percentage && link_percentage < min_percent)
78 min_percent = link_percentage;
82 * The ratio between traffic classes will control the bandwidth
83 * percentages seen on the wire. To calculate this ratio we use
84 * a multiplier. It is required that the refill credits must be
85 * larger than the max frame size so here we find the smallest
86 * multiplier that will allow all bandwidth percentages to be
87 * greater than the max frame size.
89 min_multiplier = (min_credit / min_percent) + 1;
91 /* Find out the link percentage for each TC first */
92 for (i = 0; i < MAX_TRAFFIC_CLASS; i++) {
93 p = &dcb_config->tc_config[i].path[direction];
94 bw_percent = dcb_config->bw_percentage[direction][p->bwg_id];
96 link_percentage = p->bwg_percent;
97 /* Must be careful of integer division for very small nums */
98 link_percentage = (link_percentage * bw_percent) / 100;
99 if (p->bwg_percent > 0 && link_percentage == 0)
102 /* Save link_percentage for reference */
103 p->link_percent = (u8)link_percentage;
105 /* Calculate credit refill ratio using multiplier */
106 credit_refill = min(link_percentage * min_multiplier,
108 p->data_credits_refill = (u16)credit_refill;
110 /* Calculate maximum credit for the TC */
111 credit_max = (link_percentage * MAX_CREDIT) / 100;
114 * Adjustment based on rule checking, if the percentage
115 * of a TC is too small, the maximum credit may not be
116 * enough to send out a jumbo frame in data plane arbitration.
118 if (credit_max && (credit_max < min_credit))
119 credit_max = min_credit;
121 if (direction == DCB_TX_CONFIG) {
123 * Adjustment based on rule checking, if the
124 * percentage of a TC is too small, the maximum
125 * credit may not be enough to send out a TSO
126 * packet in descriptor plane arbitration.
128 if ((hw->mac.type == ixgbe_mac_82598EB) &&
130 (credit_max < MINIMUM_CREDIT_FOR_TSO))
131 credit_max = MINIMUM_CREDIT_FOR_TSO;
133 dcb_config->tc_config[i].desc_credits_max =
137 p->data_credits_max = (u16)credit_max;
145 * ixgbe_dcb_hw_config - Config and enable DCB
146 * @hw: pointer to hardware structure
147 * @dcb_config: pointer to ixgbe_dcb_config structure
149 * Configure dcb settings and enable dcb mode.
151 s32 ixgbe_dcb_hw_config(struct ixgbe_hw *hw,
152 struct ixgbe_dcb_config *dcb_config)
155 if (hw->mac.type == ixgbe_mac_82598EB)
156 ret = ixgbe_dcb_hw_config_82598(hw, dcb_config);
157 else if (hw->mac.type == ixgbe_mac_82599EB)
158 ret = ixgbe_dcb_hw_config_82599(hw, dcb_config);